Hypothesis

The manipulation of nanosheets on a fluid-fluid interface remains a significant challenge. At this interface, hydrodynamic forces can be used for long-range transport (>1× capillary length) but are difficult to utilize for accurate and repeatable positioning. While capillary multipole interactions have been used for particle trapping, how these interactions manifest on large but thin objects, i.e., nanosheets, remains an open question. Hence, we posit hydrodynamic forces in conjunction with capillary multipole interactions can be used for nanosheet transport and trapping.

Experiments

We designed and characterized a fluidic device for transporting and trapping nanosheets on the water-air interface. Analytical models were compared against optical measurements of the nanosheet behavior to investigate capillary multipole interactions. Energy-based modeling and dimensional analysis were used to study trapping stability.

Findings

Hydrodynamic forces and capillary interactions successfully transported and trapped nanosheets at a designated trapping location with a repeatability of 10% of the nanosheet’s length and 12% of its width (length = 1500 µm, width = 1000 µm) and an accuracy of 20% of their length and width. Additionally, this is the first report that surface tension forces acting upon nanoscale-thick objects manifest as capillary quadrupolar interactions and can be used for precision manipulation of nanosheets.

中文翻译：

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通过流体动力和曲率诱导的毛细管四极相互作用的纳米片的运输和捕获。

假设

在流体-流体界面上操作纳米片仍然是一个重大挑战。在此界面上，流体动力可用于远距离传输（> 1x毛细管长度），但难以用于精确和可重复的定位。尽管毛细管多极相互作用已用于颗粒捕集，但是这些相互作用如何在大而薄的物体（即纳米片）上显现仍然是一个悬而未决的问题。因此，我们认为与毛细多极相互作用相结合的水动力可以用于纳米片的运输和捕获。

实验

我们设计并表征了一种用于在水-空气界面上运输和捕获纳米片的流体装置。将分析模型与纳米片行为的光学测量结果进行比较，以研究毛细管多极相互作用。基于能量的建模和尺寸分析用于研究捕集阱的稳定性。

发现

流体动力和毛细管相互作用在指定的捕集位置成功地运输和捕获了纳米片，其重复性为纳米片长度的10％和宽度的12％（长度= 1500 µm，宽度= 1000 µm），精度为纳米片的20％长和宽。此外，这是第一个报道，作用在纳米级厚物体上的表面张力表现为毛细管四极相互作用，可用于纳米片的精密处理。